US4580288A - Receiver input circuit - Google Patents

Receiver input circuit Download PDF

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Publication number
US4580288A
US4580288A US06/478,522 US47852283A US4580288A US 4580288 A US4580288 A US 4580288A US 47852283 A US47852283 A US 47852283A US 4580288 A US4580288 A US 4580288A
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United States
Prior art keywords
signal
input
control
network
receiver
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Expired - Lifetime
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US06/478,522
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English (en)
Inventor
Heinz Rinderle
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TELFUNKEN ELECTRONIC THERESIENSTR 2 D-7100 HEILBRONN GERMANY GmbH
Telefunken Electronic GmbH
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Telefunken Electronic GmbH
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Assigned to TELFUNKEN ELECTRONIC GMBH, THERESIENSTR. 2, D-7100 HEILBRONN, GERMANY reassignment TELFUNKEN ELECTRONIC GMBH, THERESIENSTR. 2, D-7100 HEILBRONN, GERMANY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: RINDERLE, HEINZ
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/3052—Automatic control in amplifiers having semiconductor devices in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/3052—Automatic control in amplifiers having semiconductor devices in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver
    • H03G3/3057—Automatic control in amplifiers having semiconductor devices in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver using at least one diode as controlling device

Definitions

  • Receiver input circuits comprising a preamplifier arrangement followed by a mixer arrangement which are connected to one another by adjustable selection means and whose total amplification is controlled and regulated in dependence upon signal input are used, for example, in input circuits for radio and television receivers.
  • this problem is mainly dealt with by appropriate selection of the active semiconductor components and by amplification control. This problem is caused by the limited dynamic characteristics of the passive and active semiconductor components such as bipolar transistors, field-effect transistors and diodes, including tuning diodes.
  • the block wiring diagram on page 39 of this publication shows, for example, the set-up of a VHF/UHF input section for a TV receiver with an input high-pass filter, followed by a PIN control network, antenna filter for VHF and UHF input sections, uncontrolled preamplifier stages for VHF and UHF and also, for example, band filters tuned with varactor diodes between preamplifier and following mixer stage.
  • Amplification control is effected from a higher input signal level via the PIN diode control network, with the control signal being taken from the IF section of the receiver.
  • This type of amplification control serves to protect the semiconductor components, in this case, bipolar transistors and varactor diodes, from stronger signal drives causing distortions.
  • the basic advantage of such amplification control with PIN diodes lies in the fact that the PIN diodes of the control network themselves cause practically no distortions at all.
  • the noise level increases to the same extent as the control attenuation, causing control actuation to be moved to as high as possible signal levels in order to reach a sufficiently high S/N ratio level with stronger signals at all.
  • the preamplifier transistor itself is used for amplification control.
  • amplification is lowered by upward control of the collector current of this transistor.
  • the disadvantage of such amplification control is, however, that it entails a non-linearity, dependent on the control condition and partly quite strong, which, in turn, causes signal distortions, inter alia, cross modulation and intermodulation.
  • the mixer stage is particularly endangered here if no or only insufficient amplification step-down control is possible because of the narrow band in which the control signal is gained, and if one or several strong signals reach the mixer stage, amplified or hardly attenuated because of large HF band width and corresponding low selectivity.
  • the varactor diodes used in electronic tuning also cause negative influences if they are subjected to strong signals. They themselves then cause cross modulation and intermodulation, for example, and, at certain signal levels and frequencies, can even occasion relaxation oscillations, combined with a strong modulation of the usable signals.
  • This effect is caused by the dynamic change in the average capacity of the varactor diodes with increasing applied signal voltage.
  • the varactor diodes at the output of the preamplifier stage are affected most, if, as explained above, the preamplifier stage has not or only insufficiently been subjected to step-down control. Even if no relaxation oscillations appear, mistuning of the preselection circuits may occur in the case of a received weak usable signal due to the dynamic capacity changes in the varactor diodes, weakening the usable signal reaching the mixer and thus deteriorating the S/N ratio of the usable signal received.
  • a receiver input circuit comprising a control loop for amplification control, with the control signal for the control loop being derived from the intermediate frequency signal and supplied to the part of the circuit preceding the mixer stage, in addition to a second amplification control loop whose control signal is taken out prior to the mixer stage, a third amplification control loop whose response threshold and frequency band width are lower than the response threshold and frequency band width of the first and second control circuits.
  • FIG. 1 shows the principle underlying the invention, with several amplification control circuits
  • FIG. 2 is an embodiment of a receiver input circuit
  • FIG. 3 is an embodiment with an extended, permanently tuned input network
  • FIG. 4 is an embodiment with an extended, tunable input network
  • FIG. 5 is an embodiment for the iteration-free alignment of the tuned circuits
  • FIG. 6 is an embodiment for the common tuning of a two-circuit filter with a twin varactor diode.
  • FIG. 1 shows the principle underlying a receiver input circuit 1 according to the invention with the usual functional parts such as preamplifier 4, tunable selective network 5, mixer and oscillator stage 6 and intermediate frequency selective filter 7, from which the preselected intermediate frequency signal is taken and then fed to the intermediate frequency section 13 of the receiver.
  • the use of several amplification control circuits according to the invention is shown in FIG. 1, i.e., two control circuits within the input circuit 1 and an outer control circuit which includes the intermediate frequency amplifier 13.
  • the control signal for the first control circuit is obtained at the output of the preamplifier stage (control signal line 11), for the second control circuit at the output of the mixer stage (control signal line 12), and for the third control circuit in the signal frequency selective intermediate frequency amplifier 13.
  • Amplification is controlled jointly in the input network 3 by means of the control signal 15 processed in the control signal processing circuit 10.
  • the high frequency signal voltages are converted into direct signals for the first and second control circuit in the rectifier circuits 9 and 8, respectively.
  • the effective band width is approximately identical with the transmission band width of the network 5 (HF selective filter) and the signal response threshold for control application is below the modulation limit for the mixer input or--if applicable--the varactor diodes of the selective filter 5.
  • the maximum response threshold is determined by the fact that no relaxation oscillations or control oscillations occur in the given frequency and level range, even if its amplitude is modulated.
  • the effective band width is less than that of the first control circuit but greater than that of the third control circuit and it corresponds approximately to the selective characteristics of the intermediate frequency filter 7.
  • the signal response threshold is set lower than that of the first control circuit.
  • the third amplification control circuit can be used to support the other control circuits, in which case the effective band width and the signal response threshold are lower than for the second control circuit.
  • the response threshold of the third control circuit may be controlled by the control signal, preferably of the second control circuit, in such a way that the signal response threshold is reduced by it from a certain spurious signal level on.
  • This enables the amplification of the circuit to be lowered even in the case of a small usable signal, thus affording better protection of the input circuit from the negative influences of stronger spurious signals, which is expedient and harmless if the signal noise ratio of the usable signal received were impaired by stronger spurious signals anyhow, caused, e.g., by the phase noise of the input oscillator.
  • FIG. 2 An embodiment of the input circuit according to the invention is shown in FIG. 2. This includes the input network 3 with the three reactance elements (3a, 3b, 3c) and a PIN diode 3d for controllable signal attenuation, the preamplifier stage 4 with a bipolar transistor 4b in grounded-base circuits 16 and 17, the mixer and oscillator stage 6, the intermediate frequency filter 7 with the resonant circuit 18, the rectifier circuits 8 and 9 and the control signal processing circuit 10.
  • the input network 3 with the three reactance elements (3a, 3b, 3c) and a PIN diode 3d for controllable signal attenuation
  • the preamplifier stage 4 with a bipolar transistor 4b in grounded-base circuits 16 and 17, the mixer and oscillator stage 6, the intermediate frequency filter 7 with the resonant circuit 18, the rectifier circuits 8 and 9 and the control signal processing circuit 10.
  • the signal-dependent direct signals obtained in the rectifier circuits 8 and 9 are smoothed by a capacitor 21 and directed to a controlled shunt resistor in the circuit section 10 as a control signal.
  • the shunt resistor located between the circuit point 4h and reference potential controls the direct current flowing to the PIN diode 3d, with the sum of the currents through the shunt resistor and through the PIN diode 3d being identical to the operating current of the preamplifier stage 4. Control of the PIN diode (amplification control member) is thus effected by the distribution of the operating current determined by the shunt resistor to the PIN diode and the shunt resistor.
  • This type of amplification control has the advantage that the operating current of the total circuit hardly changes at all during amplification control and that there is no substantial additional control power requirement.
  • a further advantage of this type of amplification control with the almost constant operating power during control lies in that in the case of integration of the control circuit with other circuit sections there are no substantial temperature changes in the integrated circuit during the control procedure.
  • the advantage of PIN diode control in the input network 3 in front of the first distortion-forming member (4b) is that all distortion-forming circuit components can be protected against signal overloading during control.
  • the control circuit according to the invention based on a PIN diode also has the advantage that the following amplifier component is protected against high-voltage discharge surges from the antenna.
  • rectifier circuits are generally the source of signal distortions themselves (e.g. intermodulation) it is expedient to arrange rectifier circuits 8 and/or 9 in such a way that the signal distortions which may occur do not affect the input circuit. This may be achieved, for example, by means of a buffer amplifier or amplifier component which is arranged between the signal voltage to be rectified and the rectifier circuit causing the distortions.
  • the use of a second PIN diode 3e and an extended reactance network with the additional reactances 3f to 3k is illustrated.
  • the PIN diodes act in series with respect to direct current and attenuate, on the one hand, the series-resonance of the reactance combination 3a, 3b with increasing control current flow, and, on the other hand, the parallel resonance of the parallel-resonant circuit formed by the reactances 3f and 3g.
  • the series and parallel-resonant frequency, respectively, of the reactance combinations mentioned are identical to the center frequency of the signal frequency band to be transmitted.
  • the capacitors 3h and 4f act practically as short circuits for the signal frequency.
  • FIG. 4 shows a further development of the input network.
  • a tunable selective circuit with elements 3e to 3n connected between the terminal 2 and the signal input terminal 2a.
  • This circuit has the advantage of higher selectivity while simultaneously avoiding strong attenuation of the tunable selective circuit during control.
  • the desired source impedance for actuation of the preamplifier transistor in the uncontrolled condition is adjusted, for example, by selection of the tapping of reactance 3e or by a correspondingly dimensioned coupling coil.
  • All input network circuits according to FIGS. 2 to 4 have in common the fact that during control (signal attenuation at the input) the source impedance for the preamplifier transistor 4b operating in grounded-base circuit increases.
  • the control effect is thus amplified by means of the simultaneously increasing negative current feedback without a substantial increase of the noise level during control. This is achieved by the PIN diode, whose resistance is controlled, acting at the connecting point of the reactances 3a and 3b.
  • FIG. 5 shows the tunable network in an embodiment of the invention in which the network 5, tunable by means of varactor diodes, with the resonant circuits 16 and 17 and the oscillator circuit, has a separate supply and adjustment of the tuning voltage for the varactor diodes.
  • This circuit permits an iteration-free alignment of all tunable tuning circuits of the receiver input circuit. The circuit operates as follows:
  • the manipulated variable generated by the tuning voltage generator 28 (e.g. a PLL circuit) is aligned to the minimum given tuning voltage 27 at minimum given tuning frequency by means of the oscillator circuit coil.
  • coils 16c and 17c are aligned to maximum amplification of the receiver input section at minimum signal frequency (L alignment).
  • L alignment minimum signal frequency
  • C alignment at the upper tuning frequency and signal frequency of the transmitting band this is followed by the so-called C alignment by means of the potentiometers 23, 24 and 25 in the following sequence: 25 (adjusting the upper tuning voltage) and 23 and 24 (maximum amplification).
  • one of the voltage dividers for the alignment may also be fixed voltage divider such as the divider 25 for the oscillator circuit, for example.
  • FIG. 6 shows an embodiment of the tunable network 5 with one single twin diode which forms the resonant circuit 16 and 17, respectively, with the inductance 16c and 17c, respectively, and which is supplied by a single common tuning voltage. Coupling the resonant circuits is carried out inductively in this case, with the capacitor 29 constituting in the main an HF short circuit.
  • the advantage of this embodiment of the tunable network consists in the fact that a high degree of identity of the C (U) characteristic of the varactor diodes can be expected. In this case, separate adjustment of the tuning voltage is not necessary.

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  • Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
US06/478,522 1982-03-22 1983-03-22 Receiver input circuit Expired - Lifetime US4580288A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19823210454 DE3210454A1 (de) 1982-03-22 1982-03-22 Empfaenger-eingangsschaltung
DE3210454 1982-03-22

Publications (1)

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US4580288A true US4580288A (en) 1986-04-01

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Family Applications (1)

Application Number Title Priority Date Filing Date
US06/478,522 Expired - Lifetime US4580288A (en) 1982-03-22 1983-03-22 Receiver input circuit

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US (1) US4580288A (enrdf_load_stackoverflow)
JP (1) JPS58171132A (enrdf_load_stackoverflow)
DE (1) DE3210454A1 (enrdf_load_stackoverflow)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4761828A (en) * 1984-12-24 1988-08-02 Telefunken Electronic Gmbh Radio receiver
US4776040A (en) * 1984-09-03 1988-10-04 Pioneer Electronic Corporation Superheterodyne receiver
US4792992A (en) * 1984-12-24 1988-12-20 Telfunken Electronic Gmbh Radio receiver
US4817198A (en) * 1984-12-24 1989-03-28 Telefunken Electronic Gmbh Radio receiver
US4843637A (en) * 1985-11-28 1989-06-27 Kabushiki Kaisha Toshiba Tuner circuit
US4872206A (en) * 1987-04-13 1989-10-03 Sgs-Thomson Microelectronics S.R.L. Mixer dynamic control
US5264795A (en) * 1990-06-18 1993-11-23 The Charles Machine Works, Inc. System transmitting and receiving digital and analog information for use in locating concealed conductors
US5339453A (en) * 1990-06-29 1994-08-16 Sanyo Electric Co., Ltd. AGC circuit for radio receiver having AGC sensitivity compensated by if output signal
US5483691A (en) * 1992-06-08 1996-01-09 Motorola, Inc. Zero intermediate frequency receiver having an automatic gain control circuit
US6037999A (en) * 1997-03-27 2000-03-14 Alps Electric Co., Ltd. Tuner for receiving television signal
US20020063804A1 (en) * 2000-11-29 2002-05-30 Alps Electric Co. , Ltd. Tuner for receiving television signal in VHF band and UHF band
US20020158992A1 (en) * 2000-02-08 2002-10-31 Yeo Alan Chin Leong Automatic gain control
GB2398943A (en) * 2003-02-28 2004-09-01 Zarlink Semiconductor Ltd Tuner
RU2381618C1 (ru) * 2009-02-18 2010-02-10 Федеральное государственное учреждение 16 Центральный научно-исследовательский испытательный институт Министерства обороны Российской Федерации имени маршала войск связи А.И. Белова Способ радиоприема в коротковолновом диапазоне волн

Families Citing this family (3)

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JPH0338906A (ja) * 1989-07-05 1991-02-20 Pioneer Electron Corp 受信装置
DE3942959C2 (de) * 1989-12-23 1995-06-29 Telefunken Microelectron Funkempfänger
DE4011650A1 (de) * 1990-04-11 1991-10-17 Licentia Gmbh Regelschaltung fuer einen ueberlagerungsempfaenger

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US2112279A (en) * 1935-09-10 1938-03-29 Telefunken Gmbh Automatic gain control circuits
DE673988C (de) * 1935-03-16 1939-04-01 Emi Ltd Mehrkreisiger Empfaenger mit selbsttaetiger Schwundreegelung
US3611154A (en) * 1967-12-09 1971-10-05 Philips Corp Diode switching of tuned circuits with back-bias derived from oscillator rectification
US3619786A (en) * 1966-12-30 1971-11-09 Texas Instruments Inc Solid-state vhf attenuator and tv receiver
US3895299A (en) * 1974-04-08 1975-07-15 Sanders Associates Inc Apparatus for automatic adjustment of AGC reference voltage
DE2543853A1 (de) * 1974-10-02 1976-04-15 Hitachi Ltd Empfaenger

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DE2115961C3 (de) * 1971-04-01 1978-10-05 Siemens Ag, 1000 Berlin Und 8000 Muenchen Schaltungsanordnung zur Regelung der Amplitude eines elektrischen Signals
DE2126136C3 (de) 1971-05-26 1982-07-29 Blaupunkt-Werke Gmbh, 3200 Hildesheim Regelbare HF-Eingangsstufe mit einem PIN-Dioden-Dämpfungsglied
DE2403799B2 (de) * 1974-01-26 1979-07-26 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Verstärkerschaltung mit selbsttätiger Verstärkungsregelung
DE2454187C3 (de) 1974-11-15 1978-05-18 Philips Patentverwaltung Gmbh, 2000 Hamburg Schaltungsanordnung für HF-Eingangsstufen eines Fernsehempfängers
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US2112279A (en) * 1935-09-10 1938-03-29 Telefunken Gmbh Automatic gain control circuits
US3619786A (en) * 1966-12-30 1971-11-09 Texas Instruments Inc Solid-state vhf attenuator and tv receiver
US3611154A (en) * 1967-12-09 1971-10-05 Philips Corp Diode switching of tuned circuits with back-bias derived from oscillator rectification
US3895299A (en) * 1974-04-08 1975-07-15 Sanders Associates Inc Apparatus for automatic adjustment of AGC reference voltage
DE2543853A1 (de) * 1974-10-02 1976-04-15 Hitachi Ltd Empfaenger
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Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4776040A (en) * 1984-09-03 1988-10-04 Pioneer Electronic Corporation Superheterodyne receiver
US4761828A (en) * 1984-12-24 1988-08-02 Telefunken Electronic Gmbh Radio receiver
US4792992A (en) * 1984-12-24 1988-12-20 Telfunken Electronic Gmbh Radio receiver
US4817198A (en) * 1984-12-24 1989-03-28 Telefunken Electronic Gmbh Radio receiver
US4843637A (en) * 1985-11-28 1989-06-27 Kabushiki Kaisha Toshiba Tuner circuit
US4872206A (en) * 1987-04-13 1989-10-03 Sgs-Thomson Microelectronics S.R.L. Mixer dynamic control
US5264795A (en) * 1990-06-18 1993-11-23 The Charles Machine Works, Inc. System transmitting and receiving digital and analog information for use in locating concealed conductors
US5339453A (en) * 1990-06-29 1994-08-16 Sanyo Electric Co., Ltd. AGC circuit for radio receiver having AGC sensitivity compensated by if output signal
US5483691A (en) * 1992-06-08 1996-01-09 Motorola, Inc. Zero intermediate frequency receiver having an automatic gain control circuit
GB2323727B (en) * 1997-03-27 2001-01-10 Alps Electric Co Ltd Tuner for recieving television signal
US6037999A (en) * 1997-03-27 2000-03-14 Alps Electric Co., Ltd. Tuner for receiving television signal
US20020158992A1 (en) * 2000-02-08 2002-10-31 Yeo Alan Chin Leong Automatic gain control
US7002638B2 (en) * 2000-02-08 2006-02-21 Koninklijke Philips Electronics N.V. Automatic gain control
US20020063804A1 (en) * 2000-11-29 2002-05-30 Alps Electric Co. , Ltd. Tuner for receiving television signal in VHF band and UHF band
US6903783B2 (en) * 2000-11-29 2005-06-07 Alps Electric Co., Ltd. Tuner for receiving television signal in VHF band and UHF band
GB2398943A (en) * 2003-02-28 2004-09-01 Zarlink Semiconductor Ltd Tuner
US20040229561A1 (en) * 2003-02-28 2004-11-18 Cowley Nicholas Paul Tuner
GB2398943B (en) * 2003-02-28 2005-08-31 Zarlink Semiconductor Ltd Tuner
CN1536761B (zh) * 2003-02-28 2011-09-28 英特尔公司 调谐器
RU2381618C1 (ru) * 2009-02-18 2010-02-10 Федеральное государственное учреждение 16 Центральный научно-исследовательский испытательный институт Министерства обороны Российской Федерации имени маршала войск связи А.И. Белова Способ радиоприема в коротковолновом диапазоне волн

Also Published As

Publication number Publication date
JPH0356019B2 (enrdf_load_stackoverflow) 1991-08-27
DE3210454C2 (enrdf_load_stackoverflow) 1990-10-18
JPS58171132A (ja) 1983-10-07
DE3210454A1 (de) 1983-09-22

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